When I first read this, I thought Fender was after anything S-shaped, like the superstrats that makes Ibanez. Then I went to some of the makers, like LSL, and they are making not just strato-shaped guitars but almost exact copies including the same style brigde-vibrato (when everyone is building with Evertune or Floyd), the same single coil pickups, the same knobs, the same cable socket in the front, same pickguard, same dot fret markers, same neck insertion (when everybody is using better methods for top models). They paint the guitars mimicking Fender colour schemes and even painted as aged Fenders.

Solar Guitars has a category called "S", but despite having the general shape of a Strato, the similarities end there. And they are not being threatened.

This is not "all cars have 4 wheels". This is "lets make an exact copy of a Ferrari painted in Ferrari red, that even seasoned car enthusiast would have a hard time to tell appart from a Ferrari". That said, trademarking a guitar shape that they forgot to trademark a century ago is a bad move.